The Children's Memorial Institute for Education and Research (CMIER), an affiliate of Northwestern University Medical School is an multidisciplinary research institute dedicated exclusively to pediatric research. In fiscal year 2000, there are 67 NIH funded projects by 31 different investigators. Among them, 14 NIH funded projects require the use of the flow cytometer. The whole design of the CMIER building is open and constructed to promote collaboration. We have extensive experience with core facilities including a Sequencing Core lab, tissue culture labs as well as a core Graphics facility. Several investigators within CMIER have gained experience in flow cytometry and have developed a requirement for flow cytometry to further expand their research endeavors. Currently researchers have access to a 13 year old, back up 3 color flow cytometer in the Diagnostic Immunology Laboratory which is approximately 2 blocks away from the CMIER building. This application requests a 4 color FACScalibur flow cytometer to be house within the core sequencing facility in the CMIER building. The instrument will allow us to develop a CMIER Core Flow Cytometry facility which will be administered by an Internal Advisor Committee and staffed by 2 qualified flow cytometrists under the Direction of Dr. O'Gorman who has over 20 years experience in flow cytometry and managed by Dr. Zhao who currently manages the core Sequencing facility. Currently CMIER investigators have to rely on the availability of the Clinical Lab's flow cytometer, the availability of Dr. O'Gorman and the availability of one his technologists to obtain flow cytometry. Increased need for 4 color flow cytometry has been very problematic since this technology is only available when the main clinical instrument is not being used which is very infrequent. During the past year seven investigators within CMIER have published or have manuscripts in press which utilized flow cytometry to enhance their research. The acquisition of a 4-color flow cytometer within CMIER will increase their utilization of this technology to enhance their research endeavors.